Figure 7. Brain cortex. Cells expressing p16 (A) or p21 (B) were identified by IHC staining in the brain cortex from Young, Middle-aged, and Old donors. Graph represents the quantification (%) of p16-positive cells from 5 tissue cores from independent donors per organ and age group; data represent the means ±SD from 5 different donors. p values were determined by one-way ANOVA with Tukey adjustments for multiple comparisons where appropriate. *, p < 0.05.